1913] Dickerson: Fauna of Eocene at Marysville Buttes 269 



ing down the coast, the next Eocene is reported by Gabb 14 from 

 Round Valley, Mendocino County. This is Tejon. 



Tejon is reported from Lake County, which is west of the 

 Marysville, although none is reported from along the coast of 

 Sonoma or Marin Counties or the San Francisco Peninsula. 

 The Tejon Sea probably once extended over the present site of 

 Lake County, and reached nearly continuously through Napa 

 County along the west side of the San Joaquin Valley to its 

 southern end. Extensive lava flows in Napa county prevent a 

 tracing of Tejon sediments to the Mt. Diablo region. Tejon is 

 reported on the eastern side of the San Joaquin along the Merced 

 River. The authors of the Santa Cruz folio 15 do not report any 

 Tejon, although the Butano formation may be of this age. 



Fairbanks in the San Luis folio states that during Eocene 

 times that region was a land area. Extensive Eocene deposits 

 are found, however, in Santa Barbara County immediately to the 

 south and at various other places along the coast to San Diego, 

 and Lower California as far south as 29° 30', N. latitude. 



In the discussion of bathymetric relations it was pointed out 

 that the probable depth of the Eocene sea during the time of 

 deposition of the green shales at Marysville Buttes was approxi- 

 mately 100 fathoms. As this is considerably deeper than the 

 fauna of most Tejon localities indicates as prevailing during the 

 deposition of their enclosing sediments, we may conclude that 

 in the northern portion of the state some deposits were formed 

 along the coast of an open ocean. This idea is also reenforced by 

 the statements of Thompson and Murray 10 in discussing the geo- 

 graphic distribution of glauconite. They conclude that "Where 

 the detrital matters from rivers are exceedingly abundant, and 

 where there is apparently a rapid accumulation, glauconite, 

 though present, is relatively rare ; on the other hand, along high 

 and bold coasts where no rivers enter the sea, and where accumu- 

 lation is apparently less rapid, glauconite appears in its typical 

 form and greatest abundance." 



14 Gabb, W. M., California Geological Survey, Palaeontology, vol. 2 

 (preface, p. 13), 1869. 



is Branner, J. C, Newsom, J. F., and Arnold, K., U. S. G. S., Folio 163, 

 p. 3, 1909. 



is Challenger Report, Deep Sea Deposits (p. 382), 1891. 



